Third Generation (3G) or Fourth Generation (4G) communication network systems based on the Third Generation Partnership Project (3GPP), 3GPP2, and WiMAX standards are designed to provide an Internet Protocol (IP) access function to a Mobile Station (MS). Such communication network systems configure one or more IP addresses for the mobile station, provide a transmission interface, and allow the mobile station to transmit/receive IP packets using the IP addresses. The IP packets pass through wireless and wired regions in the 3G or 4 G communication network before leaving for the Internet, oriented toward a final destination (e.g., a web server in a remote location).
Since the communication network systems are configured with mobile systems, the communication network systems also support mobility of the mobile station. This means that even though a point of attachment of the mobile station is changed from one wireless access point (e.g., a Base Station (BS)) to another wireless access point, the IP address of the mobile station is maintained to be the same as it was at a location where the mobile station was connected at that time, while the transport connection is being made. Such a function is necessary to maintain IP session continuity and IP reachability. The IP reachability refers to a reachable level of a remote peer when a new IP session is initialized by the remote peer.
If an IP address among end points is changed in a network when an IP session is in progress, common IP connections may not process the change and may also not stop the change. In a case where an IP address of a mobile station is changed, even though there is no IP session in progress, remote peers do not know the new IP address and therefore cannot reach the mobile station any more. The 3G or 4 G communication network systems allow the IP address of the mobile station to always remain the same, thereby providing continuity and reachability of the IP session. Such communication network systems provide static IP addresses to the mobile station using unique technologies.
A technology for providing an identical IP address to a mobile station entails allocating the IP address to the mobile station from a common pool managed by an exclusive entity (e.g., a Home Agent (HA) and a Packet data network GateWay (PGW)) in a core network of an operator. The HA/PGW are network nodes to which the allocated IP address belongs. This means that when a Corresponding Node (CN) transmits IP packets to the given IP address in the Internet, the packets can be automatically transmitted toward these network nodes (HA/PGW) by internet routers. The HA/PGW can intercept the IP packets for the mobile station providing services.
The next operation performed by the HA/PGW is to transmit the intercepted IP packets to any location where the mobile station is connected at that time. The location of the mobile station may be changed. Every time the mobile station changes a point of attachment, the mobile station transmits location information thereof to the HA/PGW so that the HA/PGW may always discern where the intercepted IP packets are to be sent. This method ensures that the IP packets always reach the mobile station regardless of the mobility and the location of the mobile station. This is referred to as anchoring. That is, the mobile station anchors the IP address thereof on the HA/PGW. In general, the anchoring is permanent, and the static IP address is allocated to the mobile station for an extended period of time and anchored to the core network.
FIG. 1 illustrates an example of permanent anchoring of an IP address in a core network according to the related art.
Referring to FIG. 1, first and second access networks 101 and 103 are exemplified. The first access network 101 has a hierarchical structure at a place where two base stations BS1 and BS2 are connected to an Access Router (AR) 101-1. The second access network 103 has only a base station (BS3) 103-1. In the second access network 103, the base station (BS3) 103-1 may include a function of the AR 101-1, for example, a function capable of allocating an IP address to a mobile station 10 and transmitting (forwarding/routing) IP packets. In the example of FIG. 1, a permanent IP address of the mobile station 10 for transmission/reception of IP packets between the mobile station 10 and a corresponding node 20 is anchored to an HA/PGW 102-1 in a core network 102. That is, FIG. 1 illustrates an example in which a data path between the mobile station 10 and the corresponding node 20 is made through the HA/PGW 102-1. Internet routing must be designed in such a way that the IP packets take an optimal data path when data is transmitted from one node to another node. However, in a case where the IP packets are transmitted to a third node such as the HA/PGW 102-1 as illustrated in FIG. 1, the data path cannot help but be made long. This is referred to as triangular routing (i.e., routing in which data packets between two nodes are transmitted via a fixed third point).
The triangular routing increases transmission latency of the IP packets. In the triangular routing, the IP packets must go through the longer data path and therefore it takes more time to transmit data packets to a final destination. Furthermore, in order to maintain a data path, the triangular routing requires an exclusive node such as the HA/PGW which can intercept packets instead of the mobile station and then send the packets to the mobile station at a current location. These exclusive nodes have to deal with a plurality of mobile stations at the same time. Accordingly, the exclusive nodes consume a large amount of power and require a large network capacity in order to connect the plurality of mobile stations to the Internet. Furthermore, this acts as a factor which increases address Capital Expenditure (CAPEX) and Operating Expenditure (OPEX) in the network.
In addition, unlike the routing method widely distributed in the Internet, current communication traffic is made through static nodes such as the HA/PGW. This causes failure of the data path between stations. As the communication traffic is made through the static nodes, internet routers cannot efficiently operate and reliability of the communication network is deteriorated.
Furthermore, the standby time, the increased costs, and the deteriorated reliability in the network act as loss in providing mobility of the mobile station. Accordingly, there is a need for an improved apparatus and method for efficiently managing mobility in an IP based network.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.